Power semiconductor device modules often have metal baseplates. When employed in a larger device, the module is typically fixed to a heatsink. Generally, an amount of thermal grease or a thermally conductive pad or a thermally conductive phase change material is disposed between the bottom metal surface of the baseplate and the top metal surface of the heatsink. It is desirable that there be good thermal transfer from electronic devices inside the module, through the baseplate, through any intervening amount of thermal grease or thermal pad or thermally conductive phase change material, and to the heatsink.